You'll NEVER Guess Who's Been Cast In Fifty Shades Of Grey Film...

It's been speculated for months who will play the lead roles in the Fifty Shades of Grey film, with Robert Pattinson and Emma Watson's names thrown in the mixer.

But it has finally been revealed from author EL James' own lips (or should we say tweet), that Dakota Johnson and Charlie Hunnam have been cast to play Anastasia Steele and her sadomasochistic lover Christian Grey.

She took to Twitter and wrote: "Good moaning all. Hold on to your hats... I am delighted to let you know that the lovely Dakota Johnson has agreed to be our Anastasia in the film adaptation of Fifty Shades of Grey.

Minutes later she added: ""The gorgeous and talented Charlie Hunnam will be Christian Grey in the film adaptation of Fifty Shades of Grey."

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Relative unknowns you might think, but Dakota comes from veritable acting stock, being the daughter of Don Johnson and his ex-wife Melanie Griffiths. She appeared in The Social Network and has had roles in 21 Jump Street and The Five-Year Engagement.

Charlie, 33, meanwhile, is a British actor who rose to fame back in 1999 in the TV series Queer as Folk. He also appeared in the hit cult film Sons of Anarchy. The Daily Mail reports the pair had "incredible chemistry" together during screen tests. Real-life relationship in the making, anyone? Watch this space.

Fifty Shades Of Grey - aimed at middle-aged women and credited for the rise of "mummy porn" - will be directed by Brit Sam Taylor-Johnson.

The film is set for release in August 2014.

Mel and Dakota are a famous mother-daughter duo. See more stars and their ma's here: